Function create_scatter_path

src/backend/optimizer/plan/planner.c:5614–5659

}

static Path *
create_scatter_path(PlannerInfo *root, List *scatterClause, Path *path)
{
	CdbPathLocus locus;

	/* Deal with the special case of SCATTER RANDOMLY */
	if (list_length(scatterClause) == 1 && linitial(scatterClause) == NULL)
	{
		CdbPathLocus_MakeStrewn(&locus, getgpsegmentCount(), path->parallel_workers);
	}
	else
	{
		List	   *opfamilies;
		List	   *sortrefs;
		ListCell   *lc;

		opfamilies = NIL;
		sortrefs = NIL;
		foreach(lc, scatterClause)
		{
			Node	   *expr = lfirst(lc);
			Oid			opfamily;

			opfamily = cdb_default_distribution_opfamily_for_type(exprType(expr));
			opfamilies = lappend_oid(opfamilies, opfamily);
			sortrefs = lappend_int(sortrefs, 0);
		}

		locus = cdbpathlocus_from_exprs(root,
										path->parent,
										scatterClause,
										opfamilies, sortrefs, getgpsegmentCount(), path->locus.parallel_workers);
	}

	/*
	 * Repartition the subquery plan based on our distribution
	 * requirements
	 */
	path = cdbpath_create_motion_path(root,
									  path,
									  NIL,
									  false,
									  locus);

	return path;
}

/*
 * Function: deconstruct_expr_walker